Could an eye surgery such as a cornea transplant cause a lazy eye?

No: The transplant itself doesn't cause a 'lazy eye.' lazy eye has many meanings, but to an eye doctor it means an eye that doesn't see well because the input to the brain never developed during the childhood years. Often, it is associated with a 'wandering' eye, but not always. You may have limited vision after cornea transplant, but it does not cause a lazy eye.